Spar juncture structure for wind propelled craft

Abstract

A wind propelled craft adapted for movement over water or ice having an equilateral tetrahedral frame comprising three substantially equidistantly spaced support members adapted to engage and be supported on the surface of the water, four substantially rigid spars connected together at a juncture and extending radially outward therefrom such that they are separated from each other by equal angles, and a plurality of equilength stays connected between each of the spars and the other spars at points on the spars substantially equidistant from the juncture so as to form with the spars a frame of substantially equilateral tetrahedral shape. Three of the spars extend laterally and downwardly from the juncture and are connected to the support members by stays with the fourth spar extending upwardly from the juncture. A pair of triangular mainsails are connected to respective pairs of stays extending downwardly from the vertical spar in such a manner that they are capable of being raised and lowered. Two pairs of auxiliary sails are mounted rearwardly of the mainsails. Rudders connected to the three support members, respectively, enable the craft to be steered in the desired direction.

What is claimed is: 
     
       1. A wind propelled craft adapted to move over a surface comprising: three substantially equidistantly spaced support members adapted to engage and be supported on the surface,   four substantially rigid spars connected together at a juncture and extending radially outward therefrom, each of said spars forming an angle of about 110° with each of the other spars, said spars having ends distal from the juncture,   a plurality of substantially equilength stays connected to and between each one of said spars and the other spars, respectively, said stays being connected to said spars at points substantially equidistant from said juncture so as to form with said spars a frame of substantially equilateral tetrahedral shape,   one end of each of said spars being formed as three faces of a tetrahedron, wherein said three faces converge at an apex and wherein the faces of the spars at the juncture interfit with each other to form a generally solid assembly at the juncture,   means for movably connecting three of said one ends to the fourth said one end so that said three ends can articulate about said fourth end when certain of said stays are disconnected from the spars,   three of said spars extending generally laterally and downwardly from the juncture and the fourth spar extending vertically upward from the juncture,   said support members being connected to said frame at points near the distal ends of the spars extending laterally and downwardly from the juncture, and   a sail connected to said frame.   
     
     
       2. The craft of claim 1 wherein each of said three ends includes three externally facing edges adjacent three respective externally facing edges of said fourth end, and said means for movably connecting comprises hinge means connecting said adjacent edges together. 
     
     
       3. The craft of claim 2 wherein said hinge means comprises rings passing through said fourth end and each of said three ends in the vicinity of the adjacent edges. 
     
     
       4. The craft of claim 1 wherein said ends form a generally tetrahedral assembly at said juncture.